Scientists have made people better problem solvers by applying tiny electric currents to their brains.

A gentle zapping appeared to free people from taking narrow approaches to cognitive tasks, by stimulating some regions of the brain and dampening down the activity in others.

Scientists at the University of Sydney who led the research said the work was a stepping stone towards a "dream device" that could let people see the world afresh.

The technique, called transcranial direct current stimulation (tDCS), sends apparently harmless, minuscule currents across the brain through conductive pads placed on the skull.

In the first phase of the study, 60 healthy volunteers aged 18 to 38 were set a series of problems that used matchsticks to spell out false mathematical statements with roman numerals, such as III=IX-I. To solve this particular puzzle, the matches must be rearranged as follows: III=IV-I.

The participants worked on 27 similar problems to get their brains in the habit of solving problems in a particular way. Afterwards, each volunteer was stimulated with a 1.6 milliamp current, or assigned to a control group that received the same procedure with the electricity switched off.

Five minutes later, the volunteers tackled two more sets of matchstick puzzles that required slightly different approaches, for example VI = VI + VI. In this case, the problem is solved by modifying the operator instead of the number, to give: VI = VI = VI.

The researchers found that volunteers who had electrical stimulation to their anterior temporal lobes were three times more likely to acquire the fresh insight needed to complete puzzles than the control group. The study appears in the journal, Plos One.

"Our findings demonstrate the possibility that we can modulate cognitive tradeoffs to our advantage in certain situations," Allan Snyder, director of the Centre for the Mind at the University of Sydney, told the Guardian. "They are proof of concept for the "dream" device, one that allows us to temporarily see the world anew, freeing us from entrenched mindsets."

The benefits were only seen when tDCS dampened down activity in the left anterior temporal lobe, which is associated with conceptual processing, labels and categorising, and stimulated activity in the right anterior temporal lobe, linked to insight and novel meaning.

"By artificially inducing a less filtered view of the world, we believe we can temporarily allow a less assumption-driven cognitive style, one that is crucial for creative leaps," Snyder said.

Last year, Roi Cohen Kadosh, a researcher at Oxford University, reported tDCS experiments that improved people's ability to learn mathematics. He said Snyder's work was "exciting evidence that the technique can also be used to enhance innovative thinking, or "thinking outside the box"."

"As it becomes more fashionable to use some types of drugs for cognitive enhancement, this method seems to be a good, safe, and attractive alternative," Cohen Kadosh said.